Why thunderstorms can be deadly for asthma sufferers

One of the health currencies I see every day in my surgery is asthma, with sufferers having symptoms ranging from minor to life-threatening, but many of them do not give a moment’s thought to whether that day’s weather forecast could potentially spell bad news for them.

The recent deadly ‘thunderstorm asthma’ that struck Australia is said to be the worst ever recorded with the death toll currently standing at eight (it may not be over yet, either). The previous worst episode was in London in 1994 with 640 non-fatal cases.

Recent years have seen an unexplained increase in asthma as levels of smoking and pollution have fallen over this time. However, it is now widely recognised that certain thunderstorms appear to have a strong link with severe asthma attacks and admissions to hospital and, although the exact reason is not yet fully understood, it is likely to be triggered by a combination of factors.

Small thunderstorms tend not to cause it as the humidity before the storm must be high enough so that grass pollen or fungal spores are released into the atmosphere. When large thunderstorms pass overhead they pull pollen and spores into the sky where high cloud humidity breaks these into pieces small enough to enter deep into the lungs.

These particles are then brought back down to the ground by cold, dry air flows and, since the inside of a pollen grain is highly allergenic, severe asthma reactions can occur in susceptible individuals then exposed to them.

Asthma is a chronic disease in which sufferers have repeated attacks of difficulty in breathing and coughing. People who have asthma have inflamed airways that become swollen and very sensitive. They tend to react strongly to certain inhaled substances and, when the airways react, the muscles around them tighten. This narrows the airways, causing less air to flow into the lungs and the swelling can worsen, making the airways even narrower. Cells in the airways might make more mucus than usual. Mucus is a sticky, thick liquid that can further narrow the airways.

This chain reaction can result in asthma symptoms that can happen every time the airways are inflamed.

People of all ages get asthma but 50 per cent of sufferers are children, mostly boys, under 10. Among adults, women are more likely to develop asthma than men.

Warning signals include inhaled medicines appearing less effective than usual, coughing or wheezing on exertion, night-time wakening with wheeze or cough and a fall in the peak flow meter reading (a peak flow meter is a simple device that measures the maximum speed at which a person can breathe out).

Danger signals are a bluish skin colour and gasping breath, exhaustion so severe that speech is difficult or impossible and confusion and restlessness — if any of these occur, urgent medical attention should be sought.

To help avoid an asthma attack — even if the sky is clear of thunderstorms — avoid the substances you (or the sufferer) are allergic to, if possible. It can be difficult to know which specific factors may give you trouble, but general irritants like tobacco smoke should be avoided.

It is important to take your prescribed preventive medicines, even if you feel well, and if you have a serious attack, contact your doctor or the emergency services. Discuss your treatment with your doctor or specialist – you should know what to do if, for example, you get worse during a cold. Be familiar with the use of a peak flow meter, which can help you judge your asthma during spells when it is worse and make sure you use inhaler devices correctly.

Always treat asthma earlier rather than later — fast, effective treatment may stop your symptoms from getting worse. It may also now be sensible to cast an eye at the sky and listen out for the rumble of thunder, just in case.